Residents of a village have been amazed by large rolls of 20 banknotes – usually a total of around £ 2000 – which are constantly appearing in the usual place.
12 bundles have so far appeared and been handed over to the police since 2014 – four of them this year.
Officers say they have no idea where the money comes from, but have thanked people for their honesty when handing in the bundles, reports TeessideLive.
The money has appeared in the Blackhall Colliery, north of Hartlepool in County Durham, and the last one was found on Monday.
The money always appears in a different, obvious place.
Detective Constable John Forster said officers had interviewed people and organizations in the village, in addition to performing checks with the local bank and post office and even testing for fingerprints, but the circumstances surrounding the bundles remained a mystery.
He said: “These bundles are always left without vision, for example on sidewalks and discovered by random members of the audience who have submitted them.
"This is the fourth bundle to be submitted this year. This may be the work of a good Samaritan, but we want to thank the citizens who have shown incredible community spirit by handing over the money.
"Circumstances are still mystery, so we welcome all information that will help us get to the bottom of these random events."
If you have any information, call 1[ads1]01 and ask to speak to DC Forster in Peterlee CID.
Police say the money was held for two weeks to give the owner a chance to arrive, before returning it to the applicant.